Page 1 of 1
Posted: Mon Nov 11, 2019 2:08 pm
Explain the difference between boiling points of AsF3 (63 C) and AsF5 (-53 C)
The Lewis structure for AsF3 has three As-F bonds and a lone pair whereas AsF5 had five As-F bonds. Is AsF3 a polar molecule because the As-F bonds create an unequal electron distribution with the presence of the lone pair, therefore having dipole interactions?
Posted: Mon Nov 11, 2019 2:14 pm
I believe AsF3 is a non polar molecule. The highly electronegative fluorines will direct electron density around themselves, while the lone pair around the Arsenic non bonding domain will remain. Thus, the molecule will have a net negative charge surrounding its entirety.
Posted: Tue Nov 12, 2019 5:47 pm
The boiling point of AsF3 will be higher than AsF5 since based on the Lewis structures you can determine that AsF3 is polar and AsF5 is nonpolar based on a net partial negative charge. Thus the dipole-dipole interactions for AsF3 will be stronger than AsF5 causing the boiling point to be higher.
Posted: Tue Nov 12, 2019 5:52 pm
a higher boiling point means that the elements in the molecule are highly attracted to each other i.e. the intermolecular forces are strong. because AsF3 is a polar molecule (F, as the most electromagnetic element, creates a dipole) the bonds between the elements are stronger and will take more energy to break apart (become a gas)